U.S. Patent Application Ser. No. 507,162 discloses a system for modifying the shape of a three dimensional object such as a tooth in a patient's mouth. The system includes a pantograph type assembly for feeding to a computer digitized data representing surface contours of the tooth. The pantograph assembly includes a hand-held probe inserted into the patient's mouth by a dentist. The dentist manipulates the probe so that a stylus tip of the instrument is held in contact with the tooth during tracing of a contour along the tooth. A pantograph extension outside the patient's mouth tracks the motion of the probe and particularly the stylus tip thereof, the motion of the pantograph extension being monitored by cameras which transmits video signals to the computer.
An improvement in the gathering of the contour data is disclosed in commonly owned U.S. Patent Applicatoin Ser. No. 613,354, still pending, filed Nov. 14, 1990 as a continuation-in-part of Ser. No. 507,162 still pending. In accordance with that disclosure, tape strips are adhesively applied to tooth surfaces The tape strips are formed with parallel guides such as slots or beads for guiding the stylus tip of the dental probe along a plurality of parallel lines The gathering of surface data along parallel lines greatly facilitates the processing of the data by off-the-shelf CAD/CAM programs.